Looking Up: Winter moon, high and bright

Friday

January’s full moon (and for few a few nights after) paints the landscape the most brilliantly, as it rises so high in the sky. Let’s hope for a nice coating of snow to reflect the moon’s glow.

Some have taken advantage of a clear winter night basked in lunar glow, to don cross country skis and take to the nearest field. Be careful of course, not to find yourself in trouble out in the frigid winter night- take necessary precautions, especially having a companion with you!

Just looking out the window is refreshing, to see the high winter moon bathe the yard with light. You will still see the brighter stars despite the moon, and winter has an unusual share of them. If you look out at about 10:30 p.m., the majestic constellation Orion will be due south (in early January).

Stars of all sorts

Be sure to gaze low in the southeast for the gloriously bright star Sirius, the brightest in the night sky as seen from Earth, and one of the closest stars to our solar system (only 8.7 light years away- a mere 50,460,000,000,000 miles). Rated at magnitude - 1.58, from Sirius, the sun would appear only a little brighter than the North Star. It is interesting to note that Sirius, a blue-white star twice the diameter of our sun, has a faint companion star orbiting it, a white dwarf star only three times the size of Earth. This star is so dense, that a cubic inch of its gaseous material would weigh a ton if placed on Earth.

A cubic yard of this tiny star’s material would weigh 40,000 tons. In comparison, a cubic yard of the air we breath weighs about two pounds, and a cubic yard of the sun’s material weighs around a ton. Other stars are huge. Betelgeuse, the bright red star on the upper left corner of Orion, is a red giant star. Betelgeuse is approximately 460 million miles in diameter. If substituted for our sun, Betelgeuse would envelope the orbits of Mercury, Venus, Earth and Mars. Its great expanse makes its gases so thin, a cubic yard weighs only 1/30th of an ounce. Betelgeuse is 272 light years away.

Be sure to look southeast in the early morning!! About 45 minutes before sunrise, brilliant planet Jupiter is about 30 degrees high, or about a third the way up. The red planet Mars, considerably dimmer, is close by, to the upper right as January begins. On Jan. 6, Mars will be astonishingly close to Jupiter, only a third of one degree - or less than half of the apparent width of the full moon. They will easily fit in the same field of view in a small telescope. Eyes alone, however, will offer a thrilling view.

Back to the moon

Ever wonder why the “Man in the Moon” figure always faces us? It is not because the moon is not spinning; its rotation rate merely matches the time it takes to orbit the Earth (27 days, eight hours). The moon always shows one side because of the tides.

The moon is believed to have been formed close to Earth, and at that time (well before your time) both worlds spun faster than they do now. Their gravity raised slight deformations in each other, gradually slowing their spins. Spin energy transferred to the moon, pushing it away. Even as we speak, the moon is slowing Earth’s spin very gradually- mostly by the tidal sloshing of the oceans - and consequently, the moon is moving away - by 1.5 inches per year.

Being smaller and lighter, the moon lost most of its spin to tidal braking long ago. Once it nearly stopped rotating, its slight elongated shape caused the moon to settle with its long axis (like the narrow end of an egg) always pointed at the Earth.

It was not until October 1959 when the Soviet Luna 3 probe went behind the moon, that we were afforded our first glimpse of the “far side.” Twenty seven Apollo astronauts, aboard nine missions, saw the other side of the moon (1968-1972). Other unmanned spacecraft, notably the highly successful Clementine spacecraft which NASA put into lunar orbit in January 1994, have mapped the far side in fine detail. The far side is full of craters and mountains, but few dark, level plains (the so-called “seas”) in contrast to the many seas on the near side making up the Man in the Moon’s face.

If the moon somehow turned around (I sure want to be out watching if it does), the lack of dark areas would make the full moon much brighter, but perhaps less appealing. Who hasn’t enjoyed seeing the faithful old Man in the Moon every since as a child we first looked up?

Happy New Year.

Keep looking up!

— Peter Becker is Managing Editor at The News Eagle in Hawley, PA. Notes are welcome at news@neagle.com. Please mention in what newspaper or web site you read this column.